Process of treating fibrous material preliminary to making pulp



Aug, 11, 1931. J. s. BUSCH 1,818,039

PROCESS OF TREATING FIBROUS MATERIAL PRELIMINARY TO MAKING PULP Filed Dec. 31, 1928 In verz'l'of-z JB/zrz S Busch.

Patented Aug. 11, 1931 UNITED STATES Jozm s. 317803, or CLOQITET, MINNESOTA PROCESS OF TREATING FIBROUS MATERIAL PRELIMINARY TO MAKING PULP Application filed December a1, 1928. Serial no. 329.505.

My invention relates to'processes of treating fibrous materialprelimi'nary to making pulp. In carrying out my process, wood or other material containing cellulse prefera ably in the form of. chips or small pieces to be considered as including small pieces. The pressure which I employ'is sufiicient to compress and at least partly crush the material and force out some of the air and moisture which it contains. When the pressure is released the tendencyof the material is to expand and resume its former shape and this causes some of the liquid surrounding it to be absorbed or soaked up. By successively applying and releasing the pressure, most of the air andmoisture originally in the chips are removed and replaced by the liquid in which the crushing operation takes place. After the initial crushing, the amount of liquid forced out of the material by each successive crushing becomes reater and its removal causes'the chips to urst, thereby producing partial separation of the fibers. When thus treated, the chips are in excellent condition to be reduced to a pulp by any of the standard types of pulping apparatus. It has been'fou'nd that the use of hot Water or chemicals such as caustic soda and lignin dissolving solutions as the liquid in which the crushing operation is performed, greatly hastens the separation of the fibers. In practice it has been found that the crushing can be readily accomplished by means of crushing rolls and that about five successive crushings will give the desired result. It is obvious that other means of applying mechanical crushing upon the chips while immersed in the liquid may be employed. I am aware of the fact that it has been proposed to grind chips while subjecting them to a small stream of water and that it has also been proposed to pass pulp between rollersin a vat containing a solution, but sofar as I am aware, it has never before been proposed to subject the chips to crushing action while submerged under a liquid prior to the pulping operation.

The full objects and advantages of my inthe axes of the rolls.

vention will appear in connection with the detailed description thereof, and the novel features of my inventive idea will be particularly pointed out in the claims.

In the accompanying drawing, Fig. 1 is a vertical sectional view of an apparatus suitable for carrying out my process.

Referring to the construction shown in the drawing, the numeral 10 designates a receptacle in the upper portion of which there are two cooperating crushing rolls 12 and 14. A hopper '16 at the top of the receptaclelO is arranged to deliver chips of the materialto be treated between the crushing rolls 12 and 14. The receptacle 10 has a reduced downward extension 18 containing an' upper pair of crushing rolls 20 and 22 and a lower pair of crushing rolls 24 and 26. An upwardly inclined casing 28 extends from the bottom of the extension 18. At the upper end of this casing, there is roller 30 while beyond the lower end of the casing and located in the extension 18 there is a roller 32. An endless conveyor 34 is trained around the rollers 30 and 32, the lower stretch of this convevor passing underneath a curved guide 36, while the upper stretch of the conveyor passes underneath a curved guide 38 so that the lower portion of the conveyor extends'horizontallv. The conveyor is provided with a plurality of cross pieces 40 which engage the material and move it upwardly. .The' upper end of the conveyor 34 delivers upon a horizontal conveyor 42 which takes the material to any desired place.

When the apparatus above described is employed for carrying out the process. chips of the material to be treated are fed bv the hopper 16 and drop between the rolls 12 and 14 so that the materialis crushed below the liquid level in the receptacle ,1 0. it being noted that the level of the-liquid is above Ordinarily it will be found that most of the chips will float after one crushing and some of them even aft-er two or three crushings. The floating chips will accumulate at the top of the liquid as indicated at 44 and 46 and will be carried around again between the rolls 12 and 14 until they sink in the liquid. The chips then pass between the pair of rolls 20, 22, and the pair of rolls 24,- 26, and are removed by the conveyor for susequent treatment to reduce them to pulp. My rocess produces a softened chip in which t e separation of the individual fibers com osing the chip has partially taken place. Su sequent treatment of this material in any of the standard disintegrating or pulpin machines is accomplished with a greatly re uced power consumption and with the production of a longer and stronger fiber. By performing the crushing operation under hot water, it is found that the cementing materials of the fibers in the chips are considerably softened, thus making a much easier subsequent separation. By the use of chemicals such as solution of caustic soda as the submerging liquid, the resins are dissolved in resinous woods, thus facilitating the subsequent disintegration of the chi s. My inventiveidea may be employed or impregnating wood chips with chemical solutions by mechanical means, and may be utilized in producing a semi-mechanical and chemical pulp. By performing the crushing operation ina lignin dissolving liquid orsolution, the lignin can be removed from the chips in whole or in part to produce a semi-chemical pulp. In the use of caustic soda solution, it

as been found that the use of temperatures above 212 F. greatly hastens the dissolvin of the lignin. In order to accomplish and inward movement of the chips toward,

the space between the rolls until the chips sink in the liquid.

In testimony whereof I hereunto affix my signature.

JOHN S. BUSCH.

this result, the chips impregnated with the caustic soda solution by the crushing operation may be drained, placed in a digester and subjected to steaming under pressure for a suitable period of time and at a suitable pressure after which the are dumped, washed and disintegrated; 'l h sulphate and sulphite pulping process may also be satisfactorily employed. My process provides a method of treating various woods which cannot be successfully utilized in connection with the mechanical and chemical processes now in use for making pulp. It has been found to be successful in preparing chips of pine, cedar, balm-of-Gilead, poplar, tamarack, and spruce so that such material can subsequently be defiberized by standard mechanical machines with much less difiiculty and with decreased power consumption. The process is adaptable for use with other woods and with other material, such as straw, begasse, and bamboo.

I claim:

1. The process of treating fibrous material preliminary to making pulp which consists in providing chips of the material, feeding said chips downwardly between a pair of horizontal crushing rolls which are submerged for more than half their diameter in a liquid, and repeating the crushing action of the rolls by flotation and inward movement of the-chips toward the space bee liquors used in the p 

